Ios UNUserNotificationCenter能否添加多个请求？

我可以添加一个请求。但当我试图登两条广告时，只有最新的一条被解雇了。第一个没有出现。以下是我的方法：

            var triggerDailyEnd = DateComponents()
            triggerDailyEnd.hour = hour
            triggerDailyEnd.minute = minutes
            triggerDailyEnd.weekday = i+1
            // this repeat every day
            let triggerEnd = UNCalendarNotificationTrigger(dateMatching: triggerDailyEnd, repeats: true)

            let identifierEnd = getNotificationId(i+1, hour, minutes,true)
            let requestEnd = UNNotificationRequest(identifier: identifierEnd, content: notifEnd, trigger: triggerEnd)

            notificationCenter.add(requestEnd)

            var triggerDailyStart = DateComponents()
            triggerDailyStart.hour = hour
            // correctly remove time
            triggerDailyStart.minute = minutes-Int(ProgrammationViewController.PREHEAT_TIME)
            triggerDailyStart.weekday = i+1
            // this repeat every day
            let triggerStart = UNCalendarNotificationTrigger(dateMatching: triggerDailyStart, repeats: true)

            let identifierStart = getNotificationId(i+1, hour, minutes,false)
            let requestStart = UNNotificationRequest(identifier: identifierStart, content: notifStart, trigger: triggerStart)

            notificationCenter.add(requestStart)

代码非常简单。当我在requestStart之后添加requestEnd时，会触发requestEnd通知，而不是requestStart。反之亦然。奇怪？

请求的标识符参数必须是唯一的。如果相同，则第二个请求将覆盖第一个请求